Weed, insects and pests control and crop rotation in Myanmar

Dr Laura Vickers

Harper Adams University, Crop and Environment Science

Department, Newport, Shropshire TF10 8NB

@DrLHVickers

lvickers@harper-adams.ac.uk

Example projects: • BioPesticides; Dr Rob Graham (GCRF) with Lancaster University trialing

and developing a novel cheap locally produced biopesticide in Tanzania (target African armyworm)

• Dr Tom Pope is working with Keele University and the International Centre of Insect Physiology and Ecology in Kenya to increase yields, improve worker welfare, reduce environmental impact and improve food safety by reducing pesticide residues on legumes. Part of this work involves developing a novel pheromone alternative to chemicals to thrip control in bean flower

• Dr Matthew Back is working with ICIPE and Institute of Tropical Agriculture, the Kenyan Agricultural and Livestock Research Organisation and Kenyan universities to find strategies to control PCN

Myanmar Pests and Weeds Mango: 43 insect pests and 31 microbiological disease Citrus Fruits: 31 insect pests and 8 microbiological diseases Morris and Waterhouse reported 222 arthropod pests and 170 weeds of agriculture in Myanmar. Ranking importance using 10 crops – 44 arthropods pests where considered major importance, the most important from that list being Spodoptera fitum, Helicoverpa armigem, Agrotis ipsilon, Spilarctia obliqua, Thrips palmi, Aphis gossypii, Odontotermes spp., Agrotis segetum, Boctrocera cucurbitae, Bactrocera dorsalis and Sdrtothrips dorsalis The most important weeds are Amoranthus spinosus, Cyperus iria, Cyperus rotundus, Echinochloa colonum, Fimbristylis miliacea, Impemta cylindrica, Leucas cepha/otes, Mimosa pudica, Mitracarpus villosus and Trianthema portulacastrum.

• Historically as a country low pesticide use but this is changing, found Increasing

pesticide use in Myanmar as it is being sourced from the Republic of China

Education and Regulation Issues in Myanmar

• Spraying down on calendar dates and not according to observations in the field and thresholds – essential for IPM

• Retailers provided advice regarding product choice and spray frequency to growers

• Growers relied on this advice unaware of efficiency or mode of action of pesticide

• Labels in English an issue and lack of awareness of toxicity of products and need for PPE

• 1990 The Pesticide Law outdated

Integrated Pest Management

• Combines chemical control (in rotation) when necessary with cultural and

biological control to form a comprehensive program

• Emphasizes maintaining pest levels below the economic threshold

IPM involves combining practices such as:

• selecting crops and varieties which are resistant to pest pressures

• timing planting and harvest dates to minimize pest damage

• rotating crops

• monitoring pest and natural enemy populations

• employing beneficial insects and other biological controls

The philosophy behind the IPM approach is to create unfavorable conditions for

pest buildup by enhancing crop vigor and by protecting natural enemies that

aid in controlling pest populations.

Planning in advance is vital for IPM to succeed

• Pest infestation level at which it pays to take remedial action • Set just below the economic injury level where the losses from pest damage

equals the cost of control

Knowledge cycle Know the crop’s growth characteristics to know when it is damaged Identify the pest cause of the problem Determine the stage of growth of the pest and the crop where damage occurs (for timing controls) Establish the economic threshold level Establish level of control achieved for each measure Monitor crop Implement measures Review and amend

Watermelon; Know your enemy, when it is physiology and not disease or pests!

Misshapen watermelon due to inadequate pollination

Blossom end rot caused by calcium deficiency not in the soil but in its

mobilisation around the plant through transpiration; affected by RH, wind, stomatal conductance, temperature

Varieties – questions to ask in breeding, integrate approach to other controls

Guava study in Brazil • Guava limited by root-knot nematode • Often issue is pest is misidentified on crop (multiple pest nematode

species) • Important in resistance • Screen pest for molecular markers (needs existing molecular research to

do this) • Is the population of pest homogenous? If it is then genetic resistance in

the host would be effective control • This study only one Guava rootstock had resistance and was compatible to

the commercial Guava – work ongoing • But crop rotations are possible to clean up infested areas, 14 fruit trees

are non-host to the nematode whilst 4 are good hosts

Crop rotations

• Mango, avacado, guava, durian, lychee – provide long-term, stable environments for pests and natural enemies offering 30- year cycles. Crop rotation is an option on a long term scale

• Less stable environment where productivity in crop reduces after 5-12 years i.e. banana, papaya and dragon fruit means crop rotation can be considered an shorter timescale

• Works best for oligophagous pests

• Overall avoidance in planting same-type in orchards for more than two crop cycles. Solution; keeping records, land passports has been discussed in Europe where a lot of fresh produce land is rented

Mixed cropping

• Intercropping Intermixed within a row • Strip cropping Different crops grown in rows close to another, better to allow mechanisation Benefits = mix N fixing legume crops to enhance soil fertility, wind barrier, microclimate manipulation, improved weed control, improved habitat for natural enemies and potential for a trap crop 50% reduction in insect pest populations Reduction of 60% in monophagous pests, 30% in polyphagous pests (Andow, 1991) Cons = Specific choice for the agri-system, labour intensive

Pineapple case study Weeds: Coir dust used in Sri Lanka but had a negative impact on crop delaying flowering, plastic and paper mulch to cover exposed soil and prevent germination and well timed herbicides can be used in combination Pests: Nematodes can cause stunting; options soil fumigation (not very green!), crop rotation (effective in Puerto Rico turning land to Pangola grass for three to supress neamtodes populations in between crops). Florida to combat mealybugs parasitic wasps used in tandem with insecticides when needed with some success Disease: Paper mulch on raised beds prevent soil fungi Phytophthora cinnamomi and P nicotianae. Hot treat planting material prior to planting Mixed cropping and rotation: In Africato avoid root-knot groundnuts, beans, rice and vegetables are included in crop rotations with pineapples. Green manure such as cowpea grown and incorporated prior to planting with legume intercropped with pineapple to provide nitrogen Take away message combination approaches work; biological , agronomic, chemical

Mango case study; Phillipines (and India) Cultural: right planting distance, periodic weeding, irrigation and drainage, pruning, spraying, etc. Pest/disease free water for irrigation and sprays Bait traps: light traps, sweet juice tuba trap Chemical: Spray at appropriate times in growth cycle (natural or chemical sprays, natural eucalyptus oil, citrus oil, cayenne pepper, soap, neem, onion and garlic spray) Biological control: Parasites like trichogramma, braconids, and pirate bug. Crop rotation or inter-cropping: reduce infestation or prevent re-infestation Scheduling production: less insect pests in summer months Remove diseased or infested fruits: burning, bury or composting them for fertilizer. Again combination approaches recommended; biological , agronomic, chemical

Key Messages

• Correct identification of pest/disease/weed needed

• Integrated pest management approaches are the best; they rely on

understanding of the crop physiology, pest physiology and interaction with

the wider biota and abiotic factors

• IPM is a case-by-case basis and evidence synthesis is key. Look to cases

around the world and regionally to inform a strategy; then trial, review,

adjust, reassess – continual cycle

• Often solutions maybe simple and low cost, however labour intensive

• Breeding requires genetic and molecular resources for that crop, often

genetic resistance works best when you have homogeneity of the pest and

conservation of wild rootstocks with genetic diversity for the host to work

with

• Combining approaches can alleviate the natural selection pressure to the

development of resistance in the pest/disease to genes or chemicals

• IPM will only work if growers are educated on the systems – regulation

and expert advice is needed. Board or Association? Role of crop

protection advisors? Would Myanmar benefit an BASIS/FACTS ‘greener’

equivalent from the UK?

Thank you